1. Field of the Invention
The subject invention generally pertains to electronic power conversion circuits, and, more specifically, to high frequency, switched mode electronic power converters. The subject matter relates to new non-isolated power conversion networks which provide high efficiency power conversion under special conditions where more conventional power conversion networks do not work as well.
2. Description of Related Art
The solution to the problem of converting power where the input to output or output to input voltage ratio is either very small or very large has traditionally relied upon tapped inductor power converters. New tapped inductor power conversion networks have been introduced that achieve reduced semiconductor and magnetic circuit element component stresses. An example of a circuit that achieves improved efficiency over the known alternatives for large input to output step down ratios is illustrated in FIG. 1. FIG. 1 is a minimum voltage tapped inductor buck converter. Compared to a simple buck converter the component stress factors for the FIG. 1 circuit are superior to the simple buck converter. M1 in FIG. 1 operates at higher duty cycle and lower current than the high side switch of the simple buck converter and M3 operates at lower duty cycle and higher current than the low side switch of the simple buck converter. The FIG. 1 circuit does not achieve zero voltage switching unless the coupled inductor has inherent to it a large amount of leakage inductance. The leakage inductance will create the potential for electromagnetic interference (emi) unless additional remedies are taken to avoid the emi problem. What is needed is a circuit that can accommodate large step down ratios without the requirement for a tapped inductor that also readily achieves zero voltage switching.